Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5805618.
A remix of https://www.thingiverse.com/thing:4979776 with elongated screw head cutouts and slight countersink on the underside.
I liked the original https://www.thingiverse.com/thing:4634422 (v 2.2 model 5) but wanted to keep the screw heads on the underside rather than screw into the cover from above to keep the BLTouch more secure against the threaded metal bracket. The original design didn't include cutouts/tolerance for the length of M3 button screws, and the remix works great for the screw head itself but was a bit tight to install with 6 or 8mm screws without bending the final product.
The elongated cutouts work better with M3x6 or M3x8 button screws without bending or risking a break on the finished piece. M3x6 screws will work, but require a little countersink to fully thread into the mount bracket. M3x8 screws are recommended.
Pictured printed in yellow for clarity in final product, but I prefer black (or a dark color) to tone down the BLTouch light (in yellow/light colors there's more bleed through).